1. Field of Invention
The present invention relates to an electronic package structure and the packaging process thereof. More particularly, the present invention relates to an electronic package structure and the packaging process thereof, by providing at least a baffle to prevent bubbles formed between the thin film and the affixture layer.
2. Description of Related Art
Following the advances in technology and development and growth of electronics industry, broad and extensive applications have been proposed for integrated circuits (ICs). In the semiconductor industry, integrated circuits (ICs) manufacture can be categorized as design of the ICs, fabrication of the ICs, packaging of the ICs and testing of the ICs. Among them, IC packaging has great influences in determining the performance of the ICs. For the level-1 packaging technology of IC packaging, there are three major types of bonding technologies: wire bonding (WB), flip chip bonding (FC) and tap automated bonding (TAB). Flip chip bonding technology has become widely used nowadays, because the flip chip package provides high-density pitch, compact size and high electrical performance.
Taking the flip chip bonding technology in combination of the anisotropic conductive film (ACF) as an example, bumps of the chip are electrically connected to the bonding pads of the chip carrier through the conductive particles within the anisotropic conductive film, while the chip and the chip carrier are physically connected by the thermosetting adhesive of the ACF. In order to enhance the bonding strength between the chip and the carrier, the adhesive of the ACF is heated through heating the chip. However, the adhesive of the ACF will release scorching gas under high temperature.
FIG. 1A is a top view of a conventional electronic package structure, while FIG. 1B is a cross-sectional view of FIG. 1A along the line I-I. For example, the electronic package structure 100 can be applied to a fingerprint sensor. Referring to the FIGS. 1A and 1B, the electronic package structure 100 includes a chip carrier 110, a plurality of chips 124, a thin film 132 and a transmission line 150. The chip 124 and the thin film 132 are attached to the surface of the chip carrier 110. The transmission line 150 is electrically connected to the lines on the surface of the chip carrier 110.
Usually, the chip 124 and the thin film 132 are attached to the surface of the chip carrier 110 by attaching the thin film 132 to an affixture layer 134, followed by attaching to the film attachment region 130 on the surface of the chip carrier 110, and then attaching the chip 124 to the chip attachment region 120 on the surface of the chip carrier 110 through an adhesive layer 122 in a flip-chip bonding manner. Then, a bond head 126 is used to directly heat the chip 124. Thus, heat is transfer from the chip 124 to the adhesive layer 122, which leads to softening of the adhesive layer 122 and the release of hot gas from the adhesive layer 122. The scorching gas released from the adhesive layer 122 will flow along the direction F1 and degrade the bonding between the thin film 132 and the affixture layer 134. Therefore, bubbles are formed between the thin film 132 and the affixture layer 134. In this case, the thin film 132 may easily peel from the affixture layer 134 and the poor connection between the thin film 132 and the affixture layer 134 hinder electrical transmission between the thin film 132 and the chip carrier 110, thus decreasing the yield of the electronic package structure.